I've downloaded lkl sources and it seems that it does not use /usr/share/keymaps file but its own file store in /where/is/lkl/keymaps.
So the correct command line seems to be for you:
./lkl -l -k us_km -o /home/joelfoust/lkl_log.log
If the results are wrong, you can try with "us_kmALT" or "us_kmUP" instead
Oliv'