Place in refrigerator: a large mixing bowl, can of evaporated milk, and metal beaters from an electric mixer to chill for 2 hours (If you are in a hurry, you can stick them in the freezer for one hour).
Meanwhile, heat the orange juice until it is fairly hot, and dissolve the jell-o mix into it. Add the sugar and lemon juice and mix well. Refrigerate the lemon mixture until it is cool.
Cut the rounded ends off on one side of the ladyfingers and line a 9-inch spring form cake pan with the ladyfingers, flat end on the bottom. Set aside.
Once the evaporated milk is sufficiently chilled, whip it with an electric beater on high until it forms soft foamy peaks. Gradually fold in the lemon mixture with a spatula.
Pour the lemon foam into the ring of ladyfingers. Refrigerate for at least 2 hours. Sprinkle chopped walnuts on top before serving.