Prepare cake mix according to package directions.
Pour into 2 greased and lightly floured 9x1 1/2-inch round baking pans.
Bake at 350° till wooden pick inserted in center comes out clean, 25 to 30 minutes.
Cool on wire racks for 10 minutes.
Remove from pans; cool thoroughly.
Drain mandarin orange sections, reserving 1/4 cup syrup.
Chop orange sections; set aside.
Soften unflavored gelatin in the reserved 1/4 cup mandarin orange syrup.
Place over hot water and stir to dissolve.
Cool slightly.
Beat together cream cheese and sugar.
Beat in egg yolks, lemon peel, and juice.
Stir in cooled gelatin.
Beat egg whites till stiff peaks form.
Whip cream.
Fold beaten egg whites, whipped cream, and chopped oranges into gelatin mixture.
Turn into an 8x1 1/2-inch round baking pan.
Chill till set.
Unmold onto bottom cake layer.
Cover with second cake layer.
Sift powdered sugar over top.