Guerlain's Aroma Allegoria Apaisant (soothing) edp has linden blossom listed as a note and it does have a beautiful gentle sweetness to it that is very spring-like to my nose. It's discontinued but pops up on *bay sometimes. I've just checked the directory here and you can do a search by note - just scroll down to the green triangle and put in the note you're interested in (or notes, just separate them with commas). I put in Linden and got a nice longish list of possibles, including Alaya Moriel's Tirzah, which sounded gorgeous and right up your street.
I love elderflowers (honderbluten in German, fleurs de sureau in French) and am completely addicted to spritzers made with elderflower cordial and fizzy water. I've not seen the flower as a note and there aren't any listed in the directory, but it would be great, especially in something cooling for summer, with a squeeze of citrus and a little nip of woods or ginger to make it last on the skin. Looking forward to hearing what's out there.