Place strawberries, elderflowers, lemon juice and calcium water into a heavy bottomed stock pot. Carefully snip individual florets into the fruit, discarding as much stem material as possible.
Over medium heat, bring fruit and flower mixture to a simmer stirring frequently.
Meanwhile, bring a water bath canner to a simmer, and prepare your jars and lids, and mix sugar and pectin into a separate bowl.When the fruit comes to a steady simmer, stir in the sugar and pectin.
Cook for 1-2 minutes until dissolved.
Ladle into sterilized half pint jars, leaving 1/4" head space. Wipe rims, and place on prepared lids and rings, screwing on finger tight.
Process in a boiling water bath, covered by at least 1" of water for 10 minutes.
Remove processed jars from canner and allow to cool completely. Check for seal and then loosen or remove rings for storage.