Halve the cherries and crack some of the stones. Put the cherries, stones, cinnamon and water into a pan and simmer till the cherries are soft. Rub the fruit through a hair or nylon sieve. Blend the cornflour with a little wine or water and stir it into the soup. Reboil and stir the soup till it thickens. Sweeten, add the wine (if used) and grated lemon rind. The soup may be served hot or iced.