I believe this is misidentified. European lace-leaf elderberry, or Sambucus nigra 'Laciniata,' has purple-black foliage and pink flowers, and blooms in spring (April/May). I have one in my garden. They weren't released on the US market until spring 2006.
This looks like it might be an American elderberry version of a lace-leaf -- Sambucus canadensis 'Laciniata.' American elderberry has green foliage and white flowers, and blooms in July. I have a species Sambucus canadensis in my garden also.
The current name is Sambucus nigra f. laciniata, there are cultivars with dark or "black" leaves but they can be green too. S. canadensis is now considered S. nigra subsp. canadensis as is S. canadensis var. laciniata, your plant looks more like S. nigra f. laciniata than the S. nigra subsp. canadensis.
I purchased this plant at a nursery, where I was informed it was a Hardy Ming Tree. It looked sort of like a Ming Aralia so I got it. All the leaves fell off when it was brought inside. I left on my patio all Winter.
This Spring it began to leaf out. It kept getting larger and growing much faster than a Ming Aralia. I couldn't figure out what it was until i saw something in a garden catalog identified as Sambucus Nigra Eva. it looked just like my plant except the foliage was dark.
I googled Sambucus species and saw this picture. Eureka! Mine is even beginning to get flower buds, and looks identical to this. Well i like the foliage and I think i will like the flowers, but the berries will have to be removed before the birds can snack on them. I don't have a carport and have a heavily wooded lot. I don't relish having purple poop allover my garden and car.(;-o