Metadata not transferred into Photoshop

I always use Lightroom to import my images into my database, and I apply copyright Metadata to each image when doing so.

I often will then use Photoshop & ACR to make the adjustments to the image, rather than use Lightroom.

It has become apparent recently that the Metadata applied on Import by Lightroom, is not being applied to the images which are then opened in Photoshop, and I have to re-apply this infomration for a 2nd time.

Can anyone explain this and let me know a way around it, so the metadata stays with the image and associated RAW file?

Thanks in advance. Graham