Theano cannot find libcuda.so

Question

I have installed theano using miniconda:

conda install theano

This installed

 libgpuarray: 0.7.6-h14c3975_0
 mkl-service: 1.1.2-py27hb2d42c5_4
 pygpu:       0.7.6-py27h3010b51_0
 theano:      1.0.2-py27h6bb024c_0

I then run my program and get the message:

 Could not initialize pygpu, support disable
 [...]
 File "pygpu/gpuarray.pyx", line 658, in pygpu.gpuarray.init
 File "pygpu/gpuarray.pyx", line 587, in pygpu.gpuarray.pygpu_init
 GpuArrayException: Could not load "libcuda.so": libcuda.so: cannot open shared object file: No such file or directory

So it cannot find libcuda. I get a similar message if I do

 python
 import pygpu
 pygpu.test()

I've got a cuda installation in /opt/cuda. libcuda.so is there, under /opt/cuda/lib64.

I have tried addign /opt/cuda/lib64 to my LD_LIBRARY_PATH without success. I have also tried multiple previous versions of theano and pygpu. It is still laughing in my face. It has been a few good hours of going back and forth without success.