I bought it few years ago, I don't remember exactly when. Probably, in 2006. It was NBS or BS already. But it has never bloomed for me. It is growing and growing new leaves continuously and at the moment has excellent roots and 7 mature leaves but I would like to see flowers too. It grows on the windowsill with additional lighting. Winter nights about 13-15 degrees Celsius (depending on the temperature outside the window. What would you suggest me to do to make it actually bloom?