  Discussing the general case of a hard partonic production process, we show
that the notion of parton energy loss is not always sufficient to fully address
medium-induced gluon radiation. The broader notion of gluon radiation
associated to a hard process has to be used, in particular when initial and
final state radiation amplitudes interfere, making the medium-induced radiated
energy different from the energy loss of any well-identified parton. Our
arguments are first presented in an abelian QED model, and then applied to
large-xF quarkonium hadroproduction. In this case, we show that the
medium-induced radiated energy is qualitatively similar (but not identical) to
the radiative energy loss of an "asymptotic massive parton" undergoing
transverse momentum broadening when travelling through the nucleus. In
particular, it scales as the incoming parton energy, which suggests to
reconsider gluon radiation as a possible explanation of large-xF quarkonium
suppression in p-A collisions. We expect a similar effect in open heavy-flavour
and possibly light-hadron hadroproduction at large xF, depending on the precise
definition of the nuclear suppression factor in the latter case.
