Juice of 2 lemons (approximately 1/2 cup)
1 Tablespoon of lavender
1/4 to 1/2 cup sugar (to taste)
2 cups water (or so)
2 cups of ice or an amount of ice cubes as you wish.

Start by making a lavender tea. Put the lavender in a tea strainer and pour 1 cup boiling water over it, let sit 5 minutes or so while you extract the lemon juice. Mix the sugar into the warm water so it dissolves easily. Mix in the lemon juice, then another cup of water, add ice to chill.
Garnish with fresh or dried lavender flowers, or whole stems as swizzle sticks.