I was concerned about my lavender cream going flat so I found a recipe that uses gelatin and modified to work with the simple syrup. Here is the recipe from the I found:

Stabilized Whipped Cream Frosting
(From: http://www.discusscooking.com/forums/f10/whipped-cream-that-remains-fluffed-15094-2.html)

2 tsp. unflavored gelatin
8 tsp. cold water
2 cups heavy whipping cream
1/2 cup confectioner’s sugar
1 tsp. vanilla extract

Chill a glass or stainless steel bowl large enough to hold 4 cups of whipped cream. Chill the beaters.

Combine the gelatin and water. Let sit for 5 minutes. Place over low heat and stir until the gelatine is completely dissolved (about 1 minute). Remove from heat and let cool.

Whip the heavy cream in the chilled bowl until it begins to thicken. Continue beating while slowly adding the sugar. Add the vanilla extract. While still beating, slowly add the gelatin. Whip until soft peaks form.

Imediately use to frost a cake, put into molds, or fill pastries. Place in the refrigerator to completely cool. The gelatin will set, stabilizing the whipped cream. When brought back to room temperature, it will not lose its volume or shape.

Greetings from Mexico!