Pachypodium horombense with LONG flower stalk

This interesting succulent is flowering for the first time.  The plant is less than 20 cm tall, but the flower stem is about 40 cm long.  The label says that on mature plants, the flower stalk will be 80 cm long!  We've been waiting ages for the flower to open.  It has looked to be close to opening for some days now, but perhaps it really won't be very long now.  What do you think?

It is extra exciting to see the flower bud reach this stage as last year the plant did develop a bud, but it was knocked off before the stem elongated.  I will photograph the flower, if and when it opens!