What is the possible cause of "hard starts" in cold weather on a 2001 Lincoln Town Car?

Car began starting hard when the weather turned cold. My mechanic did a tune up this past weekend and it started fine but the weather was in the 50's. Today we have snow coming in and I had to put the gas down and "nurse" it until it warmed up a bit; then it seems to run fine. Once the engine is warm it will start every time. Car has 92,000 miles and is in good shape otherwise. Please advise at your earliest and thanks in advance for any assistance you may be able to provide.