Make a syrup by combining the water, sugar & orange peel in a non-corrosive pan & bring to a boil. Simmer for 5 minutes. Remove from heat & let cool. Discard the orange peel. Combine the syrup, juice, juice concentrate & Grand Marnier. To freeze, follow the instructions for the Lemon Sorbet. To serve: Slice about 1/3 from the top of 6 large, smooth-skinned oranges & hollw them out. Pipe the sorbet from a pastry bak, fitted with a large star tip. Place each finished ice in the freezer until ready to serve. VARIATION: Replace the Grand Marnier with 2 tb of either anisette or Sambucca. Jim Tarantino, "Sorbets!"