Here is a little more fun. I've found that very often NumPy does exactly what I wish it would do - sometimes it's faster for me to just try things than it is to read the docs. Actually a mixture of both is best.
I think your answer is fine (and it's OK to accept it if you like). This is just "extra".
import numpy as np
a = np.arange(4,10).reshape(2,3)
wh = np.where(a>7)
gt = a>7
x = np.where(gt)
print "wh: ", wh
print "gt: ", gt
print "x: ", x
gives:
wh: (array([1, 1]), array([1, 2]))
gt: [[False False False]
[False True True]]
x: (array([1, 1]), array([1, 2]))
... but:
print "a[wh]: ", a[wh]
print "a[gt] ", a[gt]
print "a[x]: ", a[x]
gives:
a[wh]: [8 9]
a[gt] [8 9]
a[x]: [8 9]