Re: Yikes.
Hi Roxy, your Black Lace or any elder really will tolerate most soils from waterlogged to very chalky and moving them whatever time within reason does not usually cause a problem.
As everyone says, plenty of water is the secret even if it is chucking it down give it at least a bucketful a day.
The plants are usually pruned back hard in the early spring to control the growth but I would not go that far in September. However, it may help if it is a bit top heavy to prune off some of the top growth to give it a leg up. Keep checking around the plant and if you see some basal shoots sprouting it will have got over the shock of moving and started to grow again.
There was another post on here about a similar plant, try this link.
http://www.over50sforum.com/showthread.php?t=5419