Deleting photos from iPhone but not iCloud

I know this question has been asked and answered before, but my situation seems slightly different.

I ran out of space on my iPhone, so I uploaded all of my photos from my iPhone to an iPhoto library, and then deleted many of the photos from my iPhone. I am now uploading all photos from the iPhoto library to iCloud Photos. Once that's done, I want to start syncing my iPhone to iCloud Photos (which contains all of the old photos from iPhoto) so that new photos I take show up in iCloud, but I don't want it to delete the old photos that are currently in iCloud but were deleted from my phone. Is that possible?