I'm a bit confused over the correlation drawn between temperature and vapor lock with ethanol and gasoline. It may be a coincidence you have noticed, but the numbers don't really support it.
By the pure physics, ethanol has a lower vapor pressure than gasoline at any liquid temperature below 206°F (97°C). Further, ethanol had a higher vaporization temperature than gasoline. That's a primary reason that ethanol blends do not vaporize as well as gasoline in cold temperatures. There is a 1994 US EPA study (and white paper) on the evaporation of gasoline and ethanol blends. It makes for interesting reading, and may explain the symptoms you might be experiencing.
If the fuel system is sealed as it is supposed to be (no pressure leaks) the phenomenon should not occur. The pressure control for the EVAP canister and secondary pressure relief of the filler cap should maintain sufficient pressure to prevent vapor lock. That should be checked out. In the interim, running the fuel pump prime cycle several times before starting should purge the lines and fuel rails of vapor and charge them with liquid fuel.