Git lfs - "this exceeds GitHub's file size limit of 100.00 MB"

Since Git LFS 2.2.0 you can use git lfs migrate command. In your case it would look this way:

git lfs migrate import --include="*.csv"

After this, you should be able to push changes into origin.

More information about git lfs migrate is available on Git LFS 2.2.0 release note site and git-lfs-migrate command documentation.

Simply adding git-lfs configuration to an existing repository will not retroactively convert your large files to LFS support. Those large files will remain in your history and GitHub will refuse your pushes.

You need to rewrite your history to introduce git-lfs to your existing commits. I recommend the BFG repo cleaner tool, which added LFS support recently.

You should be able to convert historical usage of your CSV files by:

$ java -jar ~/bfg-1.12.5.jar --convert-to-git-lfs '*.csv' --no-blob-protection