Arum maculata or lords and ladies are a british native and come up no matter the weather throws at them. after the -27 a couple of years ago i did wonder if they'd re show. they did.
so no problems there and mine are in very deep shade to light shade. also damp/boggy in some places too.

Barbara, are you talking about Arum (greeny flowers) or Zantedeschia (white flowers)? Both can be commonly known as Arum Lilies. Whilst Zantedeschia come from South Africa and like damp ground they are supposed to be hardy but like full sun.

I've lost the two Zantedeschias I planted, either from cold winters or dryness, but my Arum italica soldiers on through the coldest winters and scorching drought, year after year. I have clumps in a place where no sun ever reaches, and it still thrives. I think it must be cast iron. I think it is a bigger, tougher version of A. maculata. Maybe this could be the plant for you, Barbaraolive. ;o)

If you want to see maculata I have some - you are welcome to come over and have a look.

If your arum lily is actually a Zantedeschia, the only one that is reliably hardy outside is Zantedeschia aethiopica 'Crowborough', which has white flowers and plain leaves. Those with spotted leaves or other colour flowers are not hardy outdoors. It will be fine in the area you describe, but a shortage of sunlight may mean fewer, or no, flowers.