  Quantum gravity is expected to remove the classical singularity that arises
as the end-state of gravitational collapse. To investigate this, we work with a
toy model of a collapsing homogeneous scalar field. We show that
non-perturbative semi-classical effects of Loop Quantum Gravity cause a bounce
and remove the black hole singularity. Furthermore, we find a critical
threshold scale, below which no horizon forms -- quantum gravity may exclude
very small astrophysical black holes.
