Why make the call on the flop if you plan on folding to a bet on the turn? That's just leaking chips, in my opinion. You aren't going to call on the flop if you think you are beaten, and if you think you are ahead, you shouldn't fold the turn if it simply doesn't bring a jack. Either fold on the flop or call the flop and plan on calling a moderate sized bet on the turn if no overcard or diamond appears.