Setting the default paper size of evince to A4

evince remembers many settings across runs, but not the paper size you use for printing, which is very annoying.

Apparently the default paper size is determined from an environment variable LC_PAPER.

If you're running tcsh like me, add this to your ~/.cshrc file:
setenv LC_PAPER "en_GB.UTF_8"

If you're running bash, you can add the following to your ~/.profile:
export LC_PAPER="en_GB.UTF_8"

If you want US Letter to be your default, and for some reason it isn't, apparently the magic value is "en_US.UTF-8@letter".