Dark Souls 2: Should I infuse, and with what?

One thing you need to know about infusing with elemental attacks in DS2 is that it scales off of another ability score. With lightning, you'll be scaling off of your Faith. So, if your Faith is low, you won't be adding that much more damage.

http://darksouls2.wiki.fextralife.com/Upgrades#x%E2%80%8D%E2%80%8DWeapons%20Upgrade%20Chart:%E2%80%8D%E2%80%8D

Head there and read up on what different infusions will add for you. Just putting lightning or fire on something now won't just make it better. You'll need to be investing in other stats to make the infusion better for you. If your only big stats are Strength and Dexterity, then you might be better off just upgrading your weapon to +10 or get a better weapon that scales better.

You can infuse your weapons, but it might be easier to just summon another player in your case.

Infusions cause your weapon to perform additional effects with varying power based on your stats (Lightning infusion scales with Faith for example).

Your best bet would be to use Gold Pine Resin. If you don't have that I reccommend summoning someone. When you infuse your weapon it costs 2000 souls and a material (Boltstone for Lightning).

The Large Club you mentioned scales very well with Strength, and when you infuse a weapon like that with Lightning it lowers the Strength scaling, which might actually cause you to deal less total damage (if your faith is low).

TL;DR: You won't benefit as much from your strength if you infuse it, and it's much cheaper/easier to just summon a friend/random guy.

You shouldn't do this just to beat one boss. Use a pine resin instead or magic weapon or dark weapon spells.

Seeing as you are using a strength based weapon, I'm assuming that your Faith and Int stats aren't too amazing. Therefore any kind of elemental infusion is probably going to do more harm than good.

For your specific query, as has been stated before, lightning infusion scales off your Faith stat, while reducing scaling in Strength and Dex by as much as 1 or 2 letters. So unless your faith stat is a decent amount (I would suggest ~20 at least), don't do it.

Instead you might want to look into either Raw or Mundane scaling. These are good options because they affect your scaling the least.

Raw will increase the base physical damage of your weapon. However this will drop your scaling down quite severely (down to D or E)

Mundane on the other hand has an interesting mechanic where it will give you an S scaling in whatever your lowest stat is. This means out of all 9 stats (vigorous, end, even attunement). So if your lowest stat is say, your Dex, at 18, that should whack on ~200 damage onto your weapon. With all your stats at a level 20 each, you should get about ~260 extra damage.

That being said, in your position, without a serious muck-around with stats and such, you're probably much better off using resins. These add 50 extra elemental damage onto your weapon, without the unwanted debuffs against your scaling.

If you haven't leveled whatever you want to infuse scales with you will actually be losing damage as it splits damage and has it scale with whatever corresponding infuse.

This is some great info, I must add under a very few instances (only 1 I know of) is infusing your Barbed Club (from the soul of the Flexile Sentry) Now adding lightning, fire ect. slight lowers your dexterity scaling and overall bonus damage if your faith/int is low but acts as if your upgrading your weapon and instead of reducing base damage it will add 42 normal damage and 20 Bleed damage plus the elemental damage you added. My faith is 7 and int is 3, yet after fire imbuing my Barbed Club +3 went from a total of 555 to 579 overall damage. I used to use lightning on it and have not found a weapon that causes more damage that can be wielded so fluidly in one hand.

Some weapons work well with the infusions like the zweihander. if you have good faith, great strength, and a little dexterity it makes your weapon pretty bad ass if you put lightning on it. The zweihander at plus 10 and infused with lightning puts 240 something in the strength and lightning category making it godly in pvp if you use it right, because if someone has good armor in physical damage, there is a chance they don't in electricity. Side note putting flame weapon on it with pyromancy is great because pyromancy as well scales with faith adding to the elemental damage. Plus the zweihanders 2 handed strong attack is a stab that knocks people on their back, as well it has a long distance it covers with its swing arc so you can hit people you are not facing.

Though the mastadon halberd is a amazing weapon, but you do not want to infuse it because of the A rank in scaling and the +10 420 damage.

Infusion will split the damage of your physical damage by half, and add it to the element of what you chose.

On top of splitting physical damage, it'll also now scale off of that respective element (Lightning = Faith)

For STR builds, it's better to apply resin instead. If you'd still want a lightning buff, Vengarl sells Lightning Pine Resins.

If you do not have access to Vengarl, then simply summon someone or Lucatiel. If you're playing SOTFS then Lucatiel will not be summonable until spoken to at Earthen Peak, as well as the dialogue flushed out.

I cannot explain how to get to Lucatiel, so simply google it.

TL;DR: Low stat of respective infusion element = lost damage. Get resin if you're STR build, buy them from Vengarl if necessary. No access? Summon someone or Lucatiel, SOTFS: Lucatiel found in Earthen Peak and google where she is.

Try magic infusion if you have good INT. (Scales on INT.)

Try lighting infusion if you have good FTH.(Scales on FTH.)

Try dark, or fire if you are good on FTH, and INT. (Scales on FTH, and INT.)

Try mundane if you have a well rounded character. (Mundane scales on lowest stat.)

You have good STR, so raw is a bad idea.

Posion and bleed do not work good with slow weapons, and most bosses can't be bleed/poisoned. So no poison/bleed

Fire's scaling is not much, so fire is good, BUT THE SMELTER DEMON!!! :(

I'd recommend normal if all of these are false.