Is the NWAdmin command (I am not an Admin ) FindWorklows will give to me this information.
you can use the gear menu in SharePoint to see the workflow inventory, which shows you all workflows of a site, a site collection or even the whole farm, depending from where you open the workflow inventory.
The screen will show you the last editor of the workflow. In the very same page you can filter the view to only show workflows of a specific author.
Will that help you?