It maybe too late
But clean it up and dont water it at the moment and wait and see
I am not an expert so I dont know for sure but plants sometimes manage to keep reserves below the surface so as long as they havent been damaged by the cold it may come back.
They dont really like frost at all though.
Alot of mine have to come back from the dead as we go away quite alot with the shows
I havent had one freeze though yet.
Good luck:)

I haven't had that experience either. Sadly, Orchids like it warm - so as Vicky said, it might be too late. I wouldn't give up quite yet, though. Keep it warm and see what happens - it might just revive. Fingers crossed!

All you can do is wait and see now but with blackened leaves it isn't too hopeful. Even had your heating come on it would presumably have been cold for parts of the day when you were away. With hindsight putting the orchid in fleece enclose might have helped... they really do love being warm.