I have just done a quick test of this. These are my findings:
When the user clicks edit in page editor mode, nothing happens at that point to the workflow states. All that this does is allow the user to edit the content.
There is an "Edit" chunk on the page editor which would allow the user to lock and unlock - this only appears to affect the current item being edited, not any related items used to render content to the page.
The same happens if the user clicks the save button. Only the current item is locked and put into the draft workflow state.
However, if the user edits some of the related content (logo, nav, footer etc...), when the user clicks the save button both the current item and the items that have been edited are locked and placed in the initial workflow state (as long as the templates standard values has an initial workflow setup of course)
These test were done on Sitecore 7.0 initial release - but I don't think the behavior has changed from 6.5 or 6.6.