There's no need to ever idle an engine until warmed up but one should drive it a bit nicer than normal, especially in extremely cold weather (sub zero) as the engines oil is thicker than normal (unless you're using a good synthetic) and thick oil doesn't flow well when it's extremely cold.
Frequent oil changes and good maintenance are far more important than the idea of warming up an engine as if you properly maintain the car, the original engine usually outlasts the rest of the car.