Rube Goldberg would have this solved quickly:
1. Air elemental enters room.
2. Wind gust blows a toy car, which is pushed across a table.
3. Car falls off table into a bucket
4. Bucket is one side of a balance that was balanced evenly, but now the bucket is lowered with the added weight of the car.
5. Other side of balance is raised, which is another bucket.
6. The rising bucket strikes a wire, completing an electrical circuit that starts a wheel turning
7. This wheel has a match attached to its side.
6. The turning wheel runs the match across a striker, which ignites the match
7. The wheel is stopped by a brake, holding the match in position... conveniently at the wick of the candle.
Air elemental leaves the room, its task complete.