Place raisins in a small bowl. Add boiling water to cover. Let stand 5 minutes; drain. In a medium saucepan stir together sugar and cornstarch. Stir in raisins, cranberries, and orange juice. Cook and stir over medium heat until bubbly. Set aside to cool slightly. Meanwhile, prepare and roll out pastry. Line a 9-inch pie plate with half of the pastry. Transfer cranberry filling to pastry-lined pie plate. Sprinkle with walnuts. Trim pastry to 1/2 inch beyond edge of pie plate. Cut remaining pastry into 1/2-inch-wide strips. Weave strips over filling for lattice crust. Press ends of strips into crust rim. Fold bottom pastry edge over strips; seal and crimp edge. To prevent overbrowning, cover edge of pie with foil.
Bake in a 375 degree F oven for 25 minutes. Remove foil; bake 25 minutes more or until golden. Cool on a wire rack. Makes 8 servings.