To trim the artichokes, break off the tough outer leaves and slice off the inner cone of the remaining leaves. Trim the outside with a paring knife, slice the hearts into quarters or eighths and place them in a glass bowl filled with water and lemon juice. Warm the olive oil in a wide skillet with a tight-fitting lid, and add the onion, flat leaf parsley and pepper. Cook together for 3 or 4 minutes. Add the artichokes, salt lightly and cook for another 3 or 4 minutes, turning the artichokes occasionally. Pour 1 cup of water over the artichokes and cover. Cook over low heat until the artichokes are tender, about 30 minutes. Add the olives during the last 10 minutes of cooking. Sprinkle with parmesan cheese. Taste and season with salt, if needed. Serve with the lemon wedges. Makes 4 servings.