This is odd, I did originally have that argument but I removed it because it didn't seem to matter - it works without ("On My Machine"(tm))
Erk - readding it and busting the cache. After I put my kids to bed I will figure out what is wrong
EDIT: the reason it works for me is because I've got this config in ~/.sqliterc:
.separator ','
Apparently at some point in the past I realised that I mostly insert csv files into it and set that default.