  Blue large-amplitude pulsators (BLAPs) are hot low-mass stars which show
large-amplitude light variations likely due to radial oscillations driven by
iron-group opacities. Period changes provide evidence of both secular
contraction and expansion amongst the class. Various formation histories have
been proposed, but none are completely satisfactory. \citet{Zhang2017} proposed
that the merger of a helium core white dwarf with a low-mass main-sequence star
(HeWD+MS) can lead to the formation of some classes of hot subdwarf. We have
analyzed these HeWD+MS merger models in more detail. Between helium-shell
ignition and full helium-core burning, the models pass through the volume of
luminosity -- gravity-- temperature space occupied by BLAPs. Periods of
expansion and contraction associated with helium-shell flashes can account for
the observed rates of period change. We argue that the HeWD+MS merger model
provides at least one BLAP formation channel.
