  We give a mathematical definition of irregular conformal blocks in the
genus-zero WZNW model for any simple Lie algebra, using modules for affine Lie
algebras whose parameters match up with those of moduli spaces of irregular
meromorphic connections. The Segal--Sugawara representation of the Virasoro
algebra is used to show that the spaces of irregular conformal blocks assemble
into a flat vector bundle over the space of tame isomonodromy times, and we
provide a universal version of the resulting flat connection. Finally we give a
generalisation of the dynamical Knizhnik--Zamolodchikov connection of
Felder--Markov--Tarasov--Varchenko.
