I'd agree fully will Mike's statements, it's a mercy ruling, one which I would probably rule in your favour however I would give you a warning/penalty for the card going off anyway.
Mike's statement about counting the deck and line of sight are all excellent examples of ratifying your starting hand and I think I would have to have serious concerns that the card was not yours to rule it dead.
I do however fully endorse the decision to kill your Kh, as it could easily be an angle shoot/collusion/cheating by an aggrieved player who is unhappy due to the other player having the set of queens.
The important thing for TD's is to consider the best interests of the game, and if their is any doubt that it is your card the best interest in this case is indeed to kill the card.
Stuart