I'm a smoker and intend to be one for a while.
That's true dedication right there!
In theory yes, it should be better at low temps. But from what I remember, the butane/propane doesn't mix evenly, so what happens is the lighter(or was it heavier?) propane burns off first, leaving you with only regular butane left in the canister. For it's intended use in stoves, this was not as much of a problem since by the time the propane burns off, it's warmed the rest of the canister enough to make the butane vaporize. But for a lighter, where you are just using it for multiple quick lights, there might be an issue. I don't think it should effect the lighter any, since the stoves didn't under any changes for this mix.
For normal cold, not the kind of deep freeze that you get in MN, I like the flint stlye lighters, they seem to light a lot easier than the piezo electric ones. If it was much colder than that, I think a zippo would work marginally better than a gas one. The easiest way is just to warm up the lighter a little bit in your hands, if that's possible.
EDIT: Here's a link i found if you want to get all technical about it
http://www.bushwalking.org.au/FAQ/FAQ_Mixtures.htm