Congratulations on not defoliating, your plant needs all the energy that the leaves make, to be able to grow her biggest and best flowers.
Only cut them off when they are really yellow.
The reason they go yellow is that the plant is taking sugars, amino acids, starches, vitamins etc from those older leaves to be used for flower growing, as it is more efficient for the plant to re-use the pre-made elements from the older leaves, than it is to grow flowers and make those growth elements from new at the same time as growing the flowers.
Had you cut off the leaves before they turned yellow, not only does this reduce the plants capacity to produce energy, thereby reducing growth, it also robs it of this vital resource of pre-made growth elements she has cleverly stored in her older leaves for use during the flowering cycle.
All of the plants energy is made in the leaves.
Less leaves = less energy production = less growth.
Besides, cutting off healthy green leaves and forcing your plant to grow new healthy green leaves is stupid in my opinion, and no doubt, the plants opinion too!
If the plant would not need those leaves, it would not grow them in the first place!
Hope this helps, Organoman.