In a small saucepan, bring the sugar, lemon juice and water to a boil over medium heat. Stir to dissolve sugar completely. Let cool.
PREPARE THE LAYERS:
Slice the cake into 3/4-inch slices. Then brush syrup over both sides of each cake slice. Quarter each slice.
Beat the cream cheese with sugar on high speed until light and fluffy. Reduce the speed to medium and slowly add the cream. Continue beating until the mixture resembles soft whipped cream.
ASSEMBLE THE TRIFLE:
Arrange half of the cake pieces in the bottom of a glass serving bowl or dish (2-quart size is sufficient). Spoon half the cream-cheese mixture over the cake in dollops; spread to the sides of the dish. Scatter half of the blueberries and strawberries on top. Repeat layering with cake, cream cheese and berries. Pile additional strawberries on top.
Cover and refrigerate until chilled (about an hour). You may also refrigerate overnight.
Notes
For a lower fat version, try using fat-free pound cake and reduced-fat cream cheese.
Try substituting raspberries for strawberries, or use all strawberries, or get creative with your berries!