Arnage? No clue, her sexual orientation hasn't been hinted at yet. Force is one of those monthly manga so the story isn't exactly proceeding at lightspeed.
As for the show (Nanoha is a franchise that as of now has 3 seasons, a movie, three finished manga and two running manga), that... entirely depends on your point of view. It's not that fanservicy (bar transformation sequences and the ocasional whatsit) and there certainly is yuri subtext among the main characters. There's only one pairing that's as blatant as Strike Witches though (and the fans of said pairing are rather fond of it. Fanatically so.), the rest is more 'only there if you really look for it' level.