Cut off the stems of the artichokes, using a sharp knife to produce a neat, flat base. Rub any cut surfaces with lemon to prevent discoloration. Trim all around the sides and base until the base is smooth and white, with the green exterior pared away.
Place the artichoke on its side on a flat surface. Slice off the top, leaving a base about 1½ inches deep. Using a paring knife, trim around the sides and bottom to remove the green exterior that remains. Don’t remove the fuzzy choke yet; it comes out easily when the artichokes are cooked.