Sun versus shade locations should have no impact on the foliage condition.....these plants are actually quite sun tolerant and will flower better in a sunnier location than they will in one that is full shade. I'd suspect that any foliage problems are associated with it being in a container. IME, these plants are not all that happy long term in a container and often potting soils/drainage can affect the foliage -- hellebores are rather prone to fungal problems if not provided drier conditions that also offer excellent drainage. I'd guess it will be much happier in the ground and you should see improvement in the quality of the foliage.

FWIW, I'd suspect the plant you are growing is actually Helleborus x hybridus. H. orientalis is a species that is almost never seen in commerce and is actually becoming quite rare in its natural habitat, as it crosses so easily with other species. H. x hybridus is also the most popular and widely sold of common hellebore selections. These hybrids are still erronously labeled and referred to as H. orientalis as a lot of their parentage was derived from this species originally.

Thanks for the info gardengal. I never knew that about the name.