Bring the water, honey, elderflowers, and lemon juice to a boil in a small saucer.
Once boiling and the honey has dissolved, remove from heat, cover, and let cool.
Once cooled, place in a sealed container and refrigerate overnight. Strain and discard the elderflowers (or save them for garnish).
Juice the lemons using whatever method you would like and cut the garnish lemons into thin slices. In a large pitcher, stick the fresh lemon slices, lemon juice, water, and simple syrup. Adjust flavoring to your likening by adding more honey or agave syrup.