Question

Which sentence uses appropriate punctuation?
Helen arrived unannounced when the house was a mess and we weren't ready for visitors.
Helen arrived unannounced. When the house was a mess and we weren't ready for visitors.
Helen arrived unannounced, when the house was a mess, and we weren't ready for visitors.

Answer 1

I would have actually written it this way

"Hellen arrived unannounced when the house was a mess, and we weren't ready for visitors."

But, I guess, the closest answer to this one would be the last option. :)

Hope this helps.