Warming it up to get the fermentation started may solve your problem. Oxygenating the cider may help as well.
I think deciding when to repitch is a judgement call. Ask three homebrewers and you'll probably get three different answers. Just my two cents, but I'd hope to see some activity within a day after it warms up. I don't know what you are fermenting in. Obviously, a carboy has more mass and won't warm up as quickly as a gallon jug. So, I'd give a larger fermenter a little more time.