Your global C:/Users/<user-name>/.gitconfig should have this includeIf:
[includeIf "gitdir:C:/Users/<user-name>/Documents/webstorm/corporate/"]
path = .gitconfig-work
with having your work Git repos in C:/Users/<user-name>/Documents/webstorm/corporate and the conditional work configuration should be located at C:/Users/<user-name>/.gitconfig-work.
That’s at least working for me in Window’s cmd and Cmder. A git config --show-origin --get user.email should than show you from where a config value is loaded/resolved.
It also seems like the conditional work configuration is only used when issued from within a Git repository.
C:\Users\<user-name>\Documents\webstorm\corporate
λ git config --show-origin --get user.email
file:C:/Users/<user-name>/.gitconfig foo@oss.com
C:\Users\<user-name>\Documents\webstorm\corporate\some-repo
λ git config --show-origin --get user.email
file:C:/Users/<user-name>/.gitconfig-work foo@company.com
C:\Users\<user-name>\Documents\webstorm\corporate\some-non-repo-dir
λ git config --show-origin --get user.email
file:C:/Users/<user-name>/.gitconfig foo@oss.com