How about a glaze instead of frosting. I like this recipe.
Lemon Glaze -
2/3 Cup Sifted Powdered sugar
2 Tablespoons Fresh Lemon Juice
1 Teaspoon Grated Lemon Rind
Put the sugar, lemon juice & lemon rind in a small bowl. Whisk together until well blended & smooth. Drizzle over lemon pound cake or any other cake.