I grew up above 10,000 ft and routinely hunt at 11-12K. For goat and sheep hunts, I've spent a lot of time even higher, up to close to 14K feet. One thing I do know is that the really fancy lighters (storm lighters) that give off the flame like a torch do not work at 10K feet or above. They'll work at 5-6K and I think I remember checking that they were only rated up to 8K elevation. That was when I had one that was given to me and found out the hard way that they would not work at higher elevations. I typically carry just a cheap cigarrette lighter that you can buy just about anywhere. Usually the clear ones that you can see if they still have any fuel left. I like the ones that you can adjust the flame height on. I've never had a problem with one lighting at high elevations. The flame can sometimes burn a little lower at the high elevations due to lack of O2, but that's why I like the adjustable flame ones so I can turn it all the way up. As long as you keep them dry, they should work. However, I also usually carry two of them just in case one gives up the ghost, plus matches, trioxane, etc. for emergencies. Forunately, I've never had to use that stuff, though.
Test
Butane lighters have always worked fine for me too in the high country. I carry a fire stick just in case, and strike anywhere matches...........
Casey