Don't cut off the immature bulb. If you were to cut off anything such as when your plant were weak and in danger, you would cut off the flower to save the plant.
The flower is now ... the new bulb is the future.
As long as your plant is healthy enough, don't cut off anything and just enjoy the bloom while your plant continues to grow.
beaniebeagle, If the plant looks healthy don't do anything to it. My L. anceps has quite often threw up spikes while have way through the next growth without any ill effect.