This is one of those cases where there are two hostas with the same name. One is registered and, therefore, the "official" version of H. 'Lemon Meringue' while the other is a non-registered plant and needs to be renamed to avoid further confusion.
 

This open-pollinated seedling of H. hypoleuca was registered by Peter Ruh of Ohio in 1991. It is a large size plant growing to around 26 inches in height with a spread of about 50 inches. The leaves are broadly ovate and lightly rippled. Pale lavender flowers bloom from mid-July into August on scapes up to 24 inches tall.

Hosta Helper will call this plant 'Lemon Meringue' (Ruh)

Originated in 2003 by Gabe Braun-Nauerz and Piet Th. Warmerdam, this non-registered cultivar is a sport of H. 'Lemon Lime'. It is a rapid growing, medium size (12 inches high) hosta. The foliage is narrowly ovate shaped, slightly wavy and has thin textured. It bears bright purple flowers in July and may re-bloom in September.

Hosta Helper will call this plant 'Lemon Meringue' (Braun-Nauerz)