Program not handling NSWorkspaceDidLaunchApplicationNotification events as desired

When I build and run my Objective-C project—consisting of the files main.m, BNRLogger.h, and BNRLogger.m—in Xcode, the function appLaunch: is supposed to be executed whenever a non-background application without the LSUIElement key in its Info.plist file launches on my MacBook. But that doesn't appear to be happening; the message "An app has started up!" doesn't show up in the Xcode console when an app (e.g., Blender) launches. What's going on? Have I failed to ensure that appLaunch: is called when an NSWorkspaceDidLaunchApplicationNotification is posted, or is no such notification being posted when an app launches?

This is what main.m looks like:

#import <Cocoa/Cocoa.h>
#import "BNRLogger.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        BNRLogger *logger = [[BNRLogger alloc] init];                
        [[NSNotificationCenter defaultCenter] addObserver:logger
                                                 selector:@selector(appLaunch:)
                                                     name:NSWorkspaceDidLaunchApplicationNotification
                                                   object:nil];
        [[NSRunLoop currentRunLoop] run];
    }
    return 0;
}

BNRLogger.h looks like this:

#import <Foundation/Foundation.h>

#ifndef BNRLogger_h
#define BNRLogger_h

@interface BNRLogger : NSObject
@end

#endif

And here are the contents of BNRLogger.m:

#import "BNRLogger.h"

@interface BNRLogger ()
- (void)appLaunch:(NSNotification *)note;
@end

@implementation BNRLogger
- (void)appLaunch:(NSNotification *)note {
    NSLog(@"An app has started up!");
}
@end