Is ‘round’ without an apostrophe wrong in these cases?

Sometimes the word around turns into round, e.g., in the following sentence:

They were going round and round in a circle.

Shouldn’t you put an apostrophe before round in such cases, from the standpoint of English orthography (i.e. the rule that when you omit some part of the original word, you put an apostrophe there)?

For example, it seems to me more natural to put an apostrophe before cause if the word is really because, e.g.:

I like coffee ’cause it makes me feel great.