Place the lentils in a large saucepan, and cover with water to 2 inches above lentils. Bring lentils to a boil; cover, reduce heat, and simmer 20 minutes or until tender. Drain well.
Combine sour cream and next 5 ingredients (sour cream through pepper) in a large bowl. Add lentils, ham, celery, and onion, and toss well.