Score ham using a sharp knife to make shallow cuts diagonally across ham to a diamond pattern. Stud with cloves. Place ham on rack in shallow roasting pan. Insert meat thermometer. Bake, uncovered, in 325 degree oven for 1-3/4 to 2-1/4 hours or till thermometer registers 140 degrees. In saucepan blend preserves with cornstarch. Stir in orange peel, juice, and cinnamon. Cook and stir till thickened and bubbly. Spoon some over ham 2 or 3 times during last 30 minutes of baking.