I made an intensely flavored broth using onions, carrots, celery, fresh thyme and smoked ham hocks (made by the Amish). I brought it to a boil and then gently simmered it for two hours or so. I saw the meat falling off the bone - that's how I knew she was ready.
I added the lentils until they were cooked (wasn't paying attention to the time, but it wasn't too long). I served it with some pecorino romano (like I always do) and also some croutons I had made (so the dish wasn't all soft textures).