  Processes commonly studied at the Large Hadron Collider (LHC) are induced by
quarks and gluons inside the protons of the LHC beams. In this letter we
demonstrate that, since protons also contain leptons, it is possible to target
lepton-induced processes at the LHC as well. In particular, by picking a lepton
from one beam and a quark from the other beam, we present for the first time a
comprehensive analysis of resonant single leptoquark (LQ) production at a
hadron collider. In the case of minimal scalar LQs, we derive novel bounds that
arise from the LHC Run II considering all possible flavour combinations of an
electron or a muon and an up ($u$), a down ($d$), a strange or a charm quark.
For the flavour combinations with a $u$ or a $d$ quark, the obtained limits
represent the most stringent constraints to date on LQs of this type. The
prospects of our method at future LHC runs are also explored. Given the
discovery reach of the proposed LQ signature, we argue that dedicated resonance
searches in final states featuring a single light lepton and a single
light-flavour jet should be added to the exotics search canon of both the ATLAS
and the CMS collaboration.
