  Detecting redshifted 21cm emission from neutral hydrogen in the early
Universe promises to give direct constraints on the epoch of reionization
(EoR). It will, though, be very challenging to extract the cosmological signal
(CS) from foregrounds and noise which are orders of magnitude larger.
Fortunately, the signal has some characteristics which differentiate it from
the foregrounds and noise, and we suggest that using the correct statistics may
tease out signatures of reionization. We generate mock datacubes simulating the
output of the Low Frequency Array (LOFAR) EoR experiment. These cubes combine
realistic models for Galactic and extragalactic foregrounds and the noise with
three different simulations of the CS. We fit out the foregrounds, which are
smooth in the frequency direction, to produce residual images in each frequency
band. We denoise these images and study the skewness of the one-point
distribution in the images as a function of frequency. We find that, under
sufficiently optimistic assumptions, we can recover the main features of the
redshift evolution of the skewness in the 21cm signal. We argue that some of
these features - such as a dip at the onset of reionization, followed by a rise
towards its later stages - may be generic, and give us a promising route to a
statistical detection of reionization.
