Curse on Hit + Arc + Spell totem Fail ?

It’s quite simple: The totem uses the skill with which it is created, which includes “Applies linked Curses on Hit”. However, the totem does not have your equipment, so does not have any linked curses to apply.

More generally, totems are affected by anything which modifies the skill itself, in particular support gems, but “linked curses” are not support gems and don’t themselves modify the skill. Totems cannot use any skill except the one they are created with, even if you have those skills on a trigger like “on Hit”. However they can activate triggered effects that are not skills.