need to restore calendar events
My 2011 iMac is running macOS High Sierra. I was removing old events from the calendar using Automator and I accidentally removed ALL events. I used Time Machine to recover these events to the calendar while disconnected from the internet so that I could download backup files of those events. Once connected to the internet, however, iCloud synchronizes to the iMac and removes all the restored events. How can I have these restored events stay?
Thank you.
iMac (27-inch Mid 2011), OS X El Capitan (10.11.2)