Delaying lily flowering

I really love oriental lilies but they usually start flowering in the middle of July, just when I'm about to go on holiday. I'm often away for much of August as well, so I end up cutting the blooms and giving them away. I've sometimes had orientals that didn't flower until September - perfect.

Are there any simple techiques for delaying the flowering? I know that commercial growers can mess about with flowering times - could a domestic grower also do that?

The only things I can think of doing are keeping the bulbs dormant and cool before planting for as long as possible, then putting the pots in a cool, shady place for much of its growing period.

Any ideas?