From this report and information from:

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=elenin&orb=1

If I understand it right, It shows its trajectory to be closest to earth on 16th and 17 of October 2011 at 0.24 AU


Physical Parameter Table
Parameter Symbol Value Units Sigma Reference Notes
comet total magnitude M1 10.2 mag 0.4 12 from 56 observations, assumed slope, autocmod 2.4c
comet total magnitude slope K1 10. n/a 12 autocmod 2.4c
comet nuclear magnitude M2 13.6 mag 0.4 12 from 131 observations, autocmod 2.4c
comet nuclear magnitude slope K2 5. n/a 12 autocmod 2.4c
comet nuclear phase coefficient PC 0.03 n/a 12 autocmod 2.4c