It's probably a little late now as the recent downpours combined with hailstorms have smashed the blossom heads but here's an easy recipe for elderflower champagne. Pick your flower heads on a sunny day so they are dry and fully openYou will need:
1 gallon of water in large bucket
7 large heads of sweet smelling elderflower
20 ozs of sugar
2 tablespoons white wine vinegar
Dissolve the sugar in the water. Strip the florets off heads of elderflower (no stalks) into the sugar water. Slice lemons and add to the bucket with the white wine vinegar. Stir and leave for 24 hours BUT NO LONGER. Strain and bottle in plastic bottles. Will be fizzy in 6 weeks or so.