Stationary shimmering ball of light.

About 7pm, someone noticed a light out over Lake Ontario.  I initially thought it was a small plane which was heading to the Toronto Island airport.  Within a few seconds I could tell that the light was stationary.  I happened to have a small telescope already setup in our spare bedroom.  I brought it out to our balcony and focused it to the light.  It was a round shimmering ball.  Not hard surfaced, but gaseous.  I could focus to the far side of the lake and see trees and buildings on the far shore.  
Focusing back on the light, it appeared to be at least ¾ of the way across the lake, maybe more.  Hard to estimate the size of the light/object:  maybe as small as a Volkswagen, or as large as a small bus?  
We were on the 16th floor our apartment building at 22 Close Avenue in Toronto.  Our vantage point was to the south.  The light/object was at about the same height as us.  Around 8pm we went inside to have dinner.  I left the table several times: the light was still in scope.  I never moved my scope once.  
Shortly after 9pm, I went back out to the balcony and before I could put my eye to the eyepiece, I could see the light was finally moving; slowly but steadily to the right, heading west towards Hamilton, Ontario.  
I lost sight of the light when it went out of view behind the corner of our apartment building.