Nice plant. Unfortunately, it will keep on growing during flower cycle. It's going to get huge! Usually these plants start to flower when the light cycle become fairly even, meaning about 12 hours of light and 12 hours of darkness. In order to force it to flower, you might consider bringing it inside for a 12 hour dark period, then put it back outside for 12 of sun. This will take alot of diligence as you always will have to be home in time to do this. You'll become a slave to the plant but in the end it will be worth it cause a plant that size will really produce. Just figure out a way to get it in and out safely, so you don't knock it over and break it or dump the soil. You might consider transplanting into a bigger pot too because it could probably use more space. What would be great is if you put a big pot on a platform like plywood with wheels so you can roll it around easily. Or maybe figure out some way to shade it so it's in complete darkness when on your balcony. Nice plant! What ferts are you using?