First, so happy you have hellebores as they are wonderful perennials that flower in winter.  Early summer or late spring is the time to cut back the faded blooming stems. Do not cut back the new green foliage. Once summer is over and winter returns do nothing. Then in early winter or when you see that your hellebore is sending up new stems to bloom you can cut the foliage to the ground. This will allow you to see the flowers better and also help to prevent leaf diseases. The good news is if you don't get around to cutting back the old flowering stems or the old foliage your hellebores will not die. They will look a bit messy and could get black fungus on the old leaves but hellebores are tough. If you would like to see a video of how I cut back my hellebore stems and leaves just visit YouTube and put in my name and hellebore pruning and see what pops up. Keep growing, Marianne Binetti