CGert, it is actually active as it has spread out in the tin.. I would leave it out over night, in a cook place. Could put it in the fridge, but then you will have to wait, probably until tomorrow afternoon , before you can bake it.
I have just bought my second starter in, I hope it didn't get too cold tonight, I'm really hoping that this time it will work but reading Gert's post I'm not sure I can go through with all the drama. If it rises Gert are you really going to EAT your little pet.?