Infuse one sprig of lavender in elderflower liqueur for at least one hour in refrigerator.
Pour glass of champagne, making sure not to fill to the top.
Add infused elderflower liqueur, including lavender sprig.
Using a peeler, peel a portion of zest from the lemon and heat with a lighter to warm oils in the zest.
Add zest to champagne.
Top with a quick squeeze of lemon juice.
Using a stirrer, gently combine components.
Garnish with extra lavender.