Could Lisinopril Be The Cause For Persistent Productive Cough?

I have been on Lisinopril for HBP for several years with no serious side effects. In late November I developed a dry cough, which over the past month has grown into a wet, mucas-y cough. I have had two x-rays, been diagnosed with bronchitis, then pneumonia, and gone through two rounds of antibiotics. The cough doesn't seem to be getting better, and I was recently put on oral Prednisone. The doctor today said that he thinks the Lisinopril may be the cause of the underlying cough. Is this possible? It doesn't seem logical to me that something I have been using for years would suddenly cause this cough. Nor does it make sense that this wet cough will stop just because I change HBP medication. Thoughts?