As particle physicists know, the detection of Higgs at the LHC will depend on the cross section for producing it as well as at what mass it is. There exists a working group Report of the LHC Higgs Cross Section Working Group .
The calculations show that the higher the mass of the Higgs the smaller the cross section of inclusive production at pp scattering in the LHC energy range.
Here are some limits already given by CMS.
The answer is patience and keeping fingers crossed that nature has a low mass Higgs.
Here is an analysis for low luminosity detection.