Ah yes I'm never that keen on syrups because of the sugar. You could infuse raw honey with the flowers? I imagine it'd be medicinal too

https://www.homegrown-kitchen.co.nz/2014/12/04/elderflower-infused-honey/

I love elderflower fritters

https://www.lilvienna.com/elderflower-fritters/

Which, drizzled with the elderflower honey, might be freaking amazing!